WASHINGTON, DC - MAY 21: U.S. Sen. Pat Roberts (R-KS) questions current and former IRS employees while the testify before the Senate Finance Committee May 21, 2013 in Washington, DC. The committee heard testimony on the topic of on "A Review of Criteria Used by the IRS to Identify 501(c)(4) Applications for Greater Scrutiny." (Photo by Win McNamee/Getty Images)2013 Getty Images

Drug cartels have been blamed for the rise in violence across the United States. They are also supposedly behind the rise of heroin use in the Midwest.

Now, one senator says drugs cartels are to blame for the border crisis.

It's a humanitarian problem, it's a border problem and it's a criminal problem with regards to drug cartels — all wrapped up into one...A very difficult situation.

- U.S. Sen. Pat Roberts

Sen. Pat Roberts of Kansas told a group of oil executives on Monday that Mexico’s notorious cartels are recruiting Central American children to enter the U.S. and become part of their lucrative drug enterprise.

After his speech at the annual convention of the Kansas Independent Oil and Gas Association, Roberts said he wasn’t referring to the 60,000 Central American immigrants who have crossed the border illegally and have made national headlines the past two months. Instead, he said, he meant “a lot of people” from 16 to 22 years old who are part of the recent influx from Guatemala, El Salvador and Honduras.

“They become the so-called mules to expand their drug operations in the United States,” Roberts said.

Roberts said cartels spread false information that President Barack Obama's two-year-old directive granting work permits to certain immigrants brought here illegally as youths would also allow Central American children to stay in the country.

"They put out a lot of information that was just simply not correct — it was an enticement for people to leave countries that are war-torn and where people do not believe there is an opportunity to succeed," he said.

Many of the Central American immigrants currently arriving in the country are between the ages of 16 and 22. He estimates the number of unaccompanied minors could grow to 100,000 if the U.S. doesn't respond quickly.

"It's a humanitarian problem, it's a border problem and it's a criminal problem with regards to drug cartels — all wrapped up into one," he said. "A very difficult situation."